The invention relates to a support surface and, more particularly, to a support surface such as a mattress or the like and a control system that effects pressure distribution to air cells that define the support surface.
Support surfaces are widely used in medical facilities and at home to provide pressure relief for immobile patients. These devices provide treatment for the prevention and cure of decubidus ulcers (bed sores) or pressure wounds. For any support surface that is an air or fluid support surface, the pressure in the air cells is controlled by some sort of valves, typically solenoid valves, or rotating valves. These valves allow air or other fluid into and out of the cells. For any one zone (i.e., the pressures are the same in those air cells), at least one, preferably two, valves allow the air to flow in or out of the air cells. Since the human body's weight is not evenly distributed (for instance, the torso zone is heavier than the foot zone), the pressures required in these zones differ. Therefore, it is not uncommon to require many valves to properly control various zones in the mattress.
Typically all these valves are located in the controller, which also houses the pump, control PC boards, tubing connections and other various mechanisms. For optimum therapy, many zones are required, which therefore require many valves and many connecting hoses. The size and the weight of the controller increases as the zone requirement increases. This in turn makes the placement of a large and heavy controller on the footboard of a hospital bed difficult. It also requires a unique controller for a unique zoned mattress as each valve assembly or valve manifold is unique to each zoned mattress.